1. Field of the Invention
The present invention relates to fasteners for securing heat sinks, and particularly to fasteners which conveniently and firmly secure a heat sink to an electronic device.
2. Description of Prior Art
Computer electronic devices such as central processing units (CPUs) frequently generate great amounts of heat. Oftentimes, a heat sink is attached onto a top surface of a CPU by using any of a variety of currently available fasteners. By removing heat from the CPU, the heat sink protects the CPU and associated components from instability and damage.
Continued development of CPUs has enabled them to perform more and more functions. Correspondingly, heat typically generated from CPUs is constantly increasing, and heat sinks are being made larger and larger. It is now commonplace that a single conventional fastener cannot adequately attach a heat sink onto a CPU. Shock or vibration occurring during the normal course of operation of a computer frequently displaces the heat sink relative to the CPU.
At least two fasteners are commonly needed to prevent such displacement. FIG. 6 shows two conventional fasteners 2 securing a heat sink 3 to a CPU mounted on a printed circuit board (PCB). A pair of retention modules 4 is mounted on the PCB, on opposite sides of the CPU. Opposite ends of each fastener 2 are engaged with opposite catches formed on the corresponding retention module 4. One fastener 2 is secured first, and then the other fastener 2 is secured. The heat sink 3 is thus attached to the CPU.
A pressing point of any such conventional fastener, which acts on the heat sink, usually does not coincide with a center of the fastener. This results in an eccentric moment occurring between the pressing point and the center of the fastener. The eccentric moment can cause the heat sink to be dislodged from the CPU when the system is subjected to shock or vibration during normal operation, thereby reducing the efficiency of heat transfer.
Furthermore, two operations must be performed to attach or remove the two fasteners 2. This makes installation of the fasteners unduly time-consuming. Moreover, if a heat sink fan is needed to enhance heat dissipation efficiency of the heat sink, additional holders or clips are required to fasten the heat sink fan. This lengthens assembly time and increases costs.
Thus, a fastener for readily and firmly attaching a heat sink to an electronic device such as a CPU is required.
Accordingly, an object of the present invention is to provide a fastener which can readily and firmly secure a heat sink to an electronic device.
In order to achieve the object set out above, a fastener of the present invention comprises a pressing frame, a pair of activating members and a pair of locking members. The pressing frame comprises a pair of longitudinal pressing portions, and four legs depending from each end of the pressing portions. A pair of pivot flanges extends outwardly from a bottom portion of each leg. A first pivot axis is thereby defined at each of opposite lateral sides of the pressing frame. The activating members are pivotally attached to opposite lateral sides of the pressing frame. Each activating member forms a pair of pegs at each of opposite ends thereof. A second pivot axis is thereby defined at each activating member. A pair of pivot arms extends from each end of each locking member. A through hole is defined in each pivot arm, for receiving the corresponding peg of the corresponding activating member. The locking members are thereby pivotally attached to the activating members. The fastener cooperates with a retention module to receive a heat sink and a fan therein. In operation of the fastener, the activating members are upwardly and inwardly rotated about the corresponding first pivot axes of the pressing frame. The locking members are thereby upwardly rotated about the corresponding second pivot axes of the activating members. Thus the locking members pressingly engage with the retention module, and the pressing frame firmly presses the fan. The heat sink can thereby be firmly secured to a CPU mounted on a PCB.
Other objects, advantages and novel features of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.